#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define dbg(...) 47
#endif
constexpr int N = 1e5 + 1;
int dp[N], lvl[N], p[N];
vector<int> g[N];
bool bridge[N];
void dfs(int u) {
for (auto v : g[u]) {
if (lvl[v] == 0) {
p[v] = u;
lvl[v] = lvl[u] + 1;
dfs(v);
dp[u] += dp[v];
} else if (lvl[v] > lvl[u]) {
dp[u]--;
} else {
dp[u]++;
}
}
dp[u]--;
if (dp[u] == 0) {
bridge[u] = true;
}
}
int jmp[N][20];
int lca(int a, int b) {
if (lvl[a] < lvl[b]) {
swap(a, b);
}
for (int i = 19; i >= 0; i--) {
int u = jmp[a][i];
if (lvl[u] >= lvl[b]) {
a = u;
}
}
if (a == b) return a;
for (int i = 19; i >= 0; i--) {
if (jmp[a][i] != jmp[b][i]) {
a = jmp[a][i];
b = jmp[b][i];
}
}
return jmp[a][0];
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
vector<int> a(m), b(m);
for (int i = 0; i < m; i++) {
cin >> a[i] >> b[i];
g[a[i]].push_back(b[i]);
g[b[i]].push_back(a[i]);
}
for (int i = 1; i <= n; i++) {
if (!lvl[i]) {
lvl[i] = 1;
dfs(i);
}
}
for (int i = 1; i <= n; i++) {
jmp[i][0] = p[i];
}
for (int j = 1; j < 20; j++) {
for (int i = 1; i <= n; i++) {
jmp[i][j] = jmp[jmp[i][j - 1]][j - 1];
}
}
set<array<int, 2>> r;
int q;
cin >> q;
while (q--) {
int s, t;
cin >> s >> t;
int k = lca(s, t);
while (s != k) {
if (bridge[s]) {
r.insert({s, p[s]});
}
s = p[s];
}
while (t != k) {
if (bridge[t]) {
r.insert({p[t], t});
}
t = p[t];
}
}
for (int i = 0; i < m; i++) {
if (a[i] != p[b[i]] && b[i] != p[a[i]]) {
cout << 'B';
} else {
int x = a[i], y = b[i];
if (lvl[x] < lvl[y]) {
swap(x, y);
}
if (!bridge[x]) {
cout << 'B';
} else {
if (r.count({a[i], b[i]})) {
cout << 'R';
} else if (r.count({b[i], a[i]})) {
cout << 'L';
} else {
cout << 'B';
}
}
}
}
return 0;
}
